Guided Tour of a Digital Camera

We're going to start with a generic tour of a typical non-SLR digital camera. Later on, we'll get into the features of digital SLR cameras, too, but if you want a great deal of detail on how dSLRs work, I recommend my companion volume, Mastering Digital SLR Photography. There's more than you ever expected to know about the digital single lens reflex camera.

Digital cameras come in many shapes and sizes. Yours might resemble one of the cameras shown in Figure 2.1, which range from ultracompacts about the size of a deck of cards (like the camera in front) to more sophisticated models like those shown in the back row.

Figure 2.1. Digital cameras come in all shapes and sizes.

Digital models look even more different from the rear. All of them will sport an LCD viewfinder, but that LCD may range in size from a puny 1.5 inches diagonally to the generous 2.5 inches shown in the model in Figure 2.2.

Figure 2.2. From the rear, digital cameras are usually dominated by their LCDs and array of controls.

For this chapter, I've chosen to illustrate how digital cameras work using a medium-range model that has lots of features. It's an electronic viewfinder (EVF) model, which provides SLR-like operation. Except for the EVF, you'll find most of the features in this camera in the majority of sub-$1,000 digital shooters.

Your camera may not look exactly like my example, which is based on an existing camera but genericized a bit in shape and layout to more closely represent cameras that are on the market. Digital cameras vary widely in appearance, but all of them share certain common components. Although the location for individual controls and features may differ slightly, and the camera body may be square, cubical, or rounded, virtually all digital cameras have a taking lens, an optical or electronic viewfinder, a color LCD display panel for previewing an image and showing menus, a shutter release, and a clutch of control buttons. You'll find the layouts in many cases are surprisingly similar to my example.

Most also have one or more slots for removable storage, such as Secure Digital or CompactFlash cards; a built-in electronic flash unit; a top-mounted monochrome LCD panel (found on digital SLRs for displaying the number of remaining exposures, current camera mode, and other status information); and a serial or USB port for connecting the camera to your computer when you want to download photos. You also might find a tripod socket, or an infrared port for wireless transmission of pictures.

We'll look at our example camera from four different views: the front, back, top plate, and the "control" side (which contains many of the important controls). The other two surfaces of the average digital camera are less interesting: the bottom side might contain a tripod socket and maybe a compartment for batteries, while the right side is gripped by the photographer and usually has little more than a cover that hides the digital memory card access slot.

It's possible that not all the terms in the following tour will be familiar to you. I'll explain about shutter speeds, f-stops, autofocusing, programmed exposures, single lens reflexes, and other topics later in this chapter. Consider this a basic orientation tour, and feel free to come back and review once you are comfortable with all the components of a digital camera.

First up is the front view, shown in Figure 2.3. I've numbered the key features and listed their functions below.

Control wheel/jog wheel. This control is usually placed near the shutter release or on the back of the camera so it can be operated easily by the index finger or thumb of the right hand. Some cameras, particularly digital SLRs, have two control wheels. This dial is used to change settings when the camera is up to your eye just before the photo is taken. For example, one camera puts the control wheel to work changing both shutter speed and aperture settings (depending on whether the shutter speed or lens opening control buttons are pressed with the other hand). The same camera uses this wheel to change filters, flip between various white balance settings, and to adjust other parameters. You'll learn more about each of these kinds of settings later in this chapter and Chapter 3.

Shutter release. Pressing the shutter release partway down locks the exposure and focus settings of most cameras and may trigger a display of information about those settings in the viewfinder. Press the shutter release down all the way to take the photo.

Microphone/speaker. Many digital cameras have voice annotation capabilities that let you record comments about each photo as it's taken. The microphone can also record sound when the camera is used in motion picture mode (which is available with many non-SLR models). Cameras also can emit sounds, either during playback of annotations/movies or to simulate the sound a mechanical shutter makes when the picture is taken.

Handgrip. The handgrip gives you something solid to hold, and helps position your fingers over the shutter release and other controls on the right side of the camera. In compact cameras, the handgrip may be small, bordering on the vestigial; as cameras grow in sophistication, their handgrips generally grow with them.

Focus ring. Digital cameras that allow manual focus may place the focusing ring around the lens, for convenience and for familiarity, because that's how focusing is done with a film camera, and for design reasons (when the ring physically moves lens elements to achieve sharp focus). Other cameras may provide manual focus using the cursor pad keys.

Zoom-ring. You'll find one of two common systems used to change the zoom setting of a digital camera. Some cameras have W (Wide) and T (Tele) buttons on the back surface of the camera, which operate a motorized zoom feature. Others operate more like traditional film cameras with manually operated zoom, often using a ring around the circumference of the lens.

Lens. Every digital camera has a lens of some sort, which usually will be marked with the actual focal length settings of the lens, plus, often, with the equivalent length for a 35mm camera. Our example camera has a 7.2mm to 50.8mm zoom lens, the equivalent of a 28mm to 200mm lens on a conventional camera. Because sensor size varies, the amount of magnification provided by a lens of a particular focal length varies from camera to camera, so equivalent focal lengths are used to make comparisons easier. I'll address this issue in more detail later in the chapter.

Filter thread. Most lens accessories attach via a screw-on thread on the front of the lens. These can range from close-up attachments to add-on wide-angle and telephoto converters that enhance the magnification range of your fixed lens. You can also attach various filters, lens hoods, and other accessories to the filter thread. The advantage of a standard screw thread on the front of your lens is that you can attach a wide variety of accessories, including inexpensive add-ons not made by your camera vendor. Note that not all cameras come with this convenient feature, and some require special adapters to attach even the simplest lens accessory.

Figure 2.3. Here's the front view of a typical digital camera.

Not shown:

The example camera uses an electronic viewfinder (EVF, an LCD screen viewed through an eyepiece), so this illustration does not show the window for an optical viewfinder, which is needed for any camera that doesn't have either an EVF or true through-the-lens viewing.

Next up is a back view of the example camera, shown in Figure 2.4.

Eyepiece. Most digital cameras have an eyepiece for viewing the optical viewfinder, electronic viewfinder, or through-the-lens view. However, an increasing number of compact digital cameras have no optical viewfinder at all and rely totally on the back-panel LCD for viewing and reviewing images. Those with viewfinders often have a control for adding plus or minus diopter correction so that photographers with vision problems can view without needing to wear their glasses. This particular camera model also has a sensor to the right of the eyepiece to turn the electronic viewfinder on and off as you move the camera to your eye.

LCD view screen. This screen can be used to display menus, for framing your compositions, previewing images, reviewing images, and for focusing (if your camera doesn't have an electronic viewfinder or SLR view). Some cameras also display status information, such as shutter speed or number of shots remaining. With most digital SLR cameras, the LCD is used only for menus, status display, and reviewing images. The dSLRs that allow previewing images before they are taken are rather few in number.

Battery compartment. Most digital cameras use removable rechargeable battery cells or packs. Others may use disposable lithium cells or standard AA batteries. The compartment may open on the back of the camera, the bottom, or one side, depending on your model.

Viewfinder controls. You may be able to adjust the type of information displayed in your camera's viewfinder. Options include a plain view, a view with focus area showing, or a complete view with all status information (such as focus, exposure, shooting mode) displayed. Choose a plain view to declutter your viewfinder, or opt for a full display to give you the most information as you shoot. Some cameras have a viewfinder control that sets whether the LCD or electronic viewfinders are used alone or in combination, while others rely on menu controls for these features.

Spot meter/spot focus control. Digital cameras sometimes have a button that switches metering or focusing into a "spot" mode that reads from a small section of the image shown in the viewfinder. You can use this control to finetune exposure or focus to a specific area.

Menu button. Pressing this button pops up various setup menus in your LCD display or electronic viewfinder. Many camera functions not controlled by specific buttons and dials can be set through menus.

Cursor controls. The cursor movement controls serve multiple functions in most cameras. You might use them to navigate menus, move from picture to picture in review mode, relocate the focusing "spot," or scroll around enlarged views of images. The button in the center selects the highlighted menu option or performs some other Enter/Return key function.

Quick view/Delete button. Automatically trashes the most recent photo you shot or lets you call the image back to the LCD screen for review.

Ports and sockets. Digital cameras bristle with various ports and sockets, ranging from DC power jacks to USB connections to audio/video OUT connectors.

Figure 2.4. The back of a digital camera is the "business" end of a digital camera.

The top view, shown in Figure 2.5, has a variety of camera controls.

Hot shoe cover. You may find a mount to hold a more powerful electronic flash unit on top of your digital camera. This "hot shoe" provides electrical contact with the camera, and is frequently protected by a plastic cover like the one shown in the illustration.

Viewfinder swivel. Your electronic or LCD viewfinder may swivel to let you point the camera in one direction and view from another angle. Some models, like our example camera, allow only a small amount of adjustment, from 0 to 90 degrees. Others let you swing the LCD out and twist it to many different angles. Several models let you point both the LCD and lens at yourself (so you can shoot a self-portrait) and automatically invert the LCD display when you've turned the viewscreen 180 degrees (to avoid the need to look at an upside-down view of yourself).

Exposure program modes. Choosing the right combination of shutter speed and lens opening can be tricky, so camera vendors have computerized the process. The example camera has five different program settings for (left to right) portraits, action photos, sunsets, night portraits, and text. These are chosen by pressing the button to the immediate right of the program mode strip. The button marked P at the far right resets the camera to normal program mode. Many cameras have these program modes on the main control dial, too.

Shutter release. As mentioned earlier, pressing the shutter release partway down locks the exposure and focus settings of most cameras, and may display those settings in the viewfinder. Press the shutter release down all the way to take the photo.

Control wheel/jog wheel. Also described above, this wheel is used to change settings just before the picture is snapped.

Access cover for flash memory card. You'll find one or more slots for solidstate memory cards underneath this hinged door.

Main control dial. This dial controls the camera's main functions, such as switching the camera on and off, changing from shooting mode to playback or movie modes, or to set up controls and transfer images from your camera to your computer.

LCD status screen. This monochrome display shows the number of pictures left, exposure program mode, and other status information. This data is sometimes repeated in the viewfinder.

Figure 2.5. The top of the camera has key controls for camera operation and exposure modes.

With many digital cameras, the left side is crowded with controls like those shown in Figure 2.6.

Flip-up electronic flash. The best electronic flash on digital cameras flip up to raise them as far from the lens as possible, to better reduce red-eye effects (which are accentuated when the lens and flash are located close together). Usually, raising the flash also turns it on, unless you've explicitly disabled the flash using your camera's controls.

Zoom ring. Changing the magnification of a lens manually with a zoom ring is usually faster than the motorized zooms some cameras have. Generally, inexpensive cameras with 3:1 or less zoom ratios use motorized zoom, while more expensive cameras with much longer zoom ratios (like the 7:1 of our example camera) use manual zoom because it's faster for such long stretches.

Macro button. Digital cameras with close-up capabilities usually have a macro button to switch to close-focusing mode. The button may be on the lens (as in this case) or located elsewhere on the camera. Many cameras let you switch into macro mode by pressing one of the cursor pad buttons, avoiding a trip to the menus.

Focus ring. Manual focus, if available, is most convenient when a ring around the lens is used to adjust the focus position.

Filter/color/contrast/exposure options. Multifunction dials are the norm with digital cameras. This one can be set to four different positions. The user then presses the button in the center of the dial and chooses the option desired with the control/jog wheel. Options for this dial include colored filters, color saturation, contrast, and exposure compensation.

Sensitivity/program mode/white balance/focus/sequence options. In this case the options are MEM (store current camera settings for instant recall); metering mode (choose segmented, spot, or center-weighted readings); PASM (select programmed exposure, aperture or shutter priority, and manual); Drive (single or multiple exposures, plus self-timer and time-lapse); WB (white-balance options); or ISO (sensor "sensitivity" or "speed").

Automatic focus/Manual focus button. I won't use a digital camera that doesn't have this kind of focus control. Press the button to toggle between automatic and manual focus. That's it! Digital SLR cameras may have an AF/M slide switch on the lens or camera body. Some digital cameras force you to switch to manual mode or use menu options to access manual focus. Ack!

External flash terminal. While many digital cameras accept detachable flash units, some of them are so sensitive to the voltage used to trip the flash that you must use only electronic flash offered by or recommended by the vendor. A better option is a standard external flash terminal like this one, which allows you to use virtually any third-party flash unit that can be used with a PC cord. If your digital camera does not have an external PC connection, you may be able to find one that slides into the hot shoe.

Eyepiece diopter correction control. If you wear glasses, use the diopter control to correct for some kinds of vision problems so you can view your subject without those spectacles.

Figure 2.6. Many frequently used controls are placed on the side for quick access during shooting.